Sorry if I confused you. I was simply trying to say that the problems you are facing, is likely due to power management kicking in. That is how I came to that conclusion, after reading your post.
So if power management, is causing the loss of sound, my suggestion is to prevent power management from kicking in. I tried to help you with my screenshot showing the power management setting for blanking, I told you to disable it.
I tried to help, its up to you man.
PS: I believe these issues to be one in the same IMO.
